x1,y1,x2,y2=map(float,input().split())
import math
s=math.sqrt((x1-x2)**2+(y1-y2)**2)
print(f'{s:.08f}')
         x1,y1,x2,y2=map(float,input().split()) x1 map(float,input().split()) map float input().split() ().split () input split y1 x2 y2 import math math s=math.sqrt((x1-x2)**2+(y1-y2)**2) s math.sqrt((x1-x2)**2+(y1-y2)**2) math.sqrt math sqrt (x1-x2)**2+(y1-y2)**2 (x1-x2)**2 x1-x2 x1 x2 2 (y1-y2)**2 y1-y2 y1 y2 2 print(f'{s:.08f}') print f'{s:.08f}' x1,y1,x2,y2=map(float,input().split()) map(float,input().split()) x1 x2,y2=map(float,input().split()) map(float,input().split()) x2 s=math.sqrt((x1-x2)**2+(y1-y2)**2) math.sqrt((x1-x2)**2+(y1-y2)**2) s y1,x2,y2=map(float,input().split()) map(float,input().split()) y1 y2=map(float,input().split()) map(float,input().split()) y2
x1,y1,x2,y2=map(float,input().split())
import math
s=math.sqrt((x1-x2)**2+(y1-y2)**2)
print(f'{s:.08f}')
        
